Study unveils extent of travel-related sleep disruption from 1.5 million nights of data

A recent collaborative study conducted by researchers at the Center for Sleep and Cognition at the NUS Yong Loo Lin School of Medicine (NUS Medicine) and ŌURA has shed new light on the impact of travel-related sleep disruption. The study, titled “Insights about Travel-Related Sleep Disruption from 1.5 Million Nights of Data,” was published in the prestigious journal SLEEP on March 24, 2025.

The researchers analyzed data from over 60,000 trips spanning more than 100 kilometers and utilized 1.5 million nights of de-identified data from the Oura Ring, providing a large-scale, real-world study of jet lag recovery. Unlike previous studies that were limited to controlled environments or specific populations, this study offers insights into the general traveling public.

Lead researcher Adrian Willoughby, Senior Research Fellow at NUS Medicine, highlighted the persistent impact of jet lag on travelers, especially in terms of adjusting sleep timing to a new time zone. The study revealed that while sleep duration bounces back relatively quickly, changes in sleep timing and structure can take longer to readjust, particularly after crossing multiple time zones.

Jet lag is not the only factor contributing to sleep disruption during travel. Early wake-up times for flights, especially for morning departures, can lead to shortened sleep the night before traveling. Overnight flights pose additional challenges, often resulting in impaired performance and increased daytime sleepiness.

The study found that while sleep duration returns to baseline within around two days, changes in sleep timing and structure, such as increased nighttime awakenings, can persist for over a week. Eastward travel and crossing multiple time zones exacerbate these disruptions.

Key findings from the study include:

• Sleep duration typically recovers quickly, aligning with habitual patterns within a few days post-travel.
• Eastward travel results in more severe jet lag, especially for shorter trips of up to three time zones. Longer journeys show similar disruptions regardless of direction, with sleep occurring significantly earlier or later than usual.
• Gender differences in travel-related sleep disruption were minimal, but older travelers experienced slightly less impact. Younger individuals saw a greater reduction in sleep duration compared to older travelers post-travel.

This study’s unique feature was its extensive measurement of habitual sleep before and after travel, providing valuable insights into real-world jet lag recovery. Wearable devices like the Oura Ring are proving to be powerful tools for collecting health data on a large scale, enabling individuals to assess their sleep patterns and recovery post-travel compared to the general population.

Future research will explore lifestyle factors that influence the speed of sleep disruption recovery, as well as the effectiveness of interventions like light exposure and melatonin ingestion in real-world settings.